Method for signaling of resource allocation to adjust granularity in cellular multi-carrier system

ABSTRACT

A method for receiving a downlink signal in a wireless mobile communication system, and an apparatus therefore; and a method for transmitting a downlink signal in a wireless mobile communication system, and an apparatus therefore are described. The method for receiving the downlink signal according to one embodiment includes receiving common downlink control information including a resource indication value, RIV. The RIV is mapped to a start index S and a length L of consecutive virtual resource blocks, VRBs. The method for receiving the downlink signal according to one embodiment further includes receiving the downlink signal on the consecutive VRBs. The RIV is mapped to the start index S and the length L of the consecutive VRBs, or else the RIV is mapped to the start index S and the length L of the consecutive VRBs.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. application Ser. No.14/579,895 filed on Dec. 22, 2014, which is a Continuation of U.S.application Ser. No. 13/966,166 filed on Aug. 13, 2013, now U.S. Pat.No. 8,958,385 issued on Feb. 17, 2015, which is a Continuation of U.S.application Ser. No. 12/987,902 filed on Jan. 10, 2011, now U.S. Pat.No. 8,532,043 issued on Sep. 10, 2013, which is a continuation of U.S.application Ser. No. 12/421,877 filed on Apr. 10, 2009, now U.S. Pat.No. 7,885,221 issued on Feb. 8, 2011, which claims the priority benefitunder 35 U.S.C. 119(e) of U.S. Provisional Application No. 61/075,010filed on Jun. 24, 2008, and U.S. Provisional Application No. 61/074,131filed on Jun. 19, 2008, and the priority benefit under 35 U.S.C. 119(a)of. Korean Patent Application No. 10-2008-0136669 filed on Dec. 30, 2008in the Republic of Korea, all of which are hereby incorporated byreference as fully set forth herein.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to a broadband wireless mobilecommunication system, and more particularly, to radio resourcescheduling for uplink/downlink packet data transmission in a cellularorthogonal frequency division multiplexing (OFDM) wireless packetcommunication system.

Discussion of the Related Art

In a cellular orthogonal frequency division multiplex (OFDM) wirelesspacket communication system, uplink/downlink data packet transmission ismade on a subframe basis and one subframe is defined by a certain timeinterval including a plurality of OFDM symbols.

The 3^(rd) Generation Partnership Project (3GPP) supports a type 1 radioframe structure applicable to frequency division duplex (FDD), and atype 2 radio frame structure applicable to time division duplex (TDD).The structure of a type 1 radio frame is shown in FIG. 1. The type 1radio frame includes ten subframes, each of which consists of two slots.The structure of a type 2 radio frame is shown in FIG. 2. The type 2radio frame includes two half-frames, each of which is made up of fivesubframes, a downlink piloting time slot (DwPTS), a gap period (GP), andan uplink piloting time slot (UpPTS), in which one subframe consists oftwo slots. That is, one subframe is composed of two slots irrespectiveof the radio frame type.

A signal transmitted from each slot can be described by a resource gridincluding N_(RB) ^(DL)N_(SC) ^(RB) subcarriers and N_(symb) ^(DL) OFDMsymbols. Here, N_(RB) ^(DL) represents the number of resource blocks(RBs) in a downlink, N_(SC) ^(RB) represents the number of subcarriersconstituting one RB, and N_(symb) ^(DL) represents the number of OFDMsymbols in one downlink slot. The structure of this resource grid isshown in FIG. 3.

RBs are used to describe a mapping relationship between certain physicalchannels and resource elements. The RBs can be divided into physicalresource blocks (PRBs) and virtual resource blocks (VRBs). A mappingrelationship between the VRBs and the PRBs can be described on asubframe basis. In more detail, it can be described in units of a slotconstituting one subframe. Also, the mapping relationship between theVRBs and the PRBs can be described using a mapping relationship betweenindexes of the VRBs and indexes of PRBs. A detailed description of thiswill be further given in embodiments of the present invention.

A PRB is defined by N_(symb) ^(DL) consecutive OFDM symbols in a timedomain and N_(SC) ^(RB) consecutive subcarriers in a frequency domain.One PRB is therefore composed of N_(symb) ^(DL)N_(SC) ^(RB) resourceelements. The PRBs are assigned numbers from 0 to N_(RB) ^(DL)−1 in thefrequency domain.

A VRB can have the same size as that of the PRB. There are two types ofVRBs defined, the first one being a localized type and the second onebeing a distributed type. For each VRB type, a pair of VRBs have asingle VRB index (may hereinafter be referred to as a ‘VRB number’) andare allocated over two slots of one subframe. In other words, N_(RB)^(DL) VRBs belonging to a first one of two slots constituting onesubframe are each assigned any one index of 0 to N_(RB) ^(DL)−1, andN_(RB) ^(DL) VRBs belonging to a second one of the two slots arelikewise each assigned any one index of 0 to N_(RB) ^(DL)−1.

The index of a VRB corresponding to a specific virtual frequency band ofthe first slot has the same value as that of the index of a VRBcorresponding to the specific virtual frequency band of the second slot.That is, assuming that a VRB corresponding to an ith virtual frequencyband of the first slot is denoted by VRB1(i), a VRB corresponding to ajth virtual frequency band of the second slot is denoted by VRB2(j) andindex numbers of the VRB1(i) and VRB2(j) are denoted by index(VRB1(i))and index(VRB2(j)), respectively, a relationship of index(VRB1(k))index(VRB2(k)) is established (see FIG. 4A).

Likewise, the index of a PRB corresponding to a specific frequency bandof the first slot has the same value as that of the index of a PRBcorresponding to the specific frequency band of the second slot. Thatis, assuming that a PRB corresponding to an ith frequency band of thefirst slot is denoted by PRB1(i), a PRB corresponding to a jth frequencyband of the second slot is denoted by PRB2(j) and index numbers of thePRB1(i) and PRB2(j) are denoted by index(PRB1(i)) and index(PRB2(j)),respectively, a relationship of index(PRB1(k))=index(PRB2(k)) isestablished (see FIG. 4B).

Some of the aforementioned VRBs are allocated as the localized type andthe others are allocated as the distributed type. Hereinafter, the VRBsallocated as the localized type will be referred to as ‘localizedvirtual resource blocks (LVRBs)’ and the VRBs allocated as thedistributed type will be referred to as ‘distributed virtual resourceblocks (DVRBs)’.

The localized VRBs (LVRBs) are directly mapped to PRBs and the indexesof the LVRBs correspond to the indexes of the PRBs. Also, LVRBs of anindex i correspond to PRBs of the index i. That is, an LVRB1 having theindex i corresponds to a PRB1 having the index i, and an LVRB2 havingthe index i corresponds to a PRB2 having the index (see FIG. 5). In thiscase, it is assumed that the VRBs of FIG. 5 are all allocated as LVRBs.

The distributed VRBs (DVRBs) may not be directly mapped to PRBs. Thatis, the indexes of the DVRBs can be mapped to the PRBs after beingsubjected to a series of processes.

First, the order of a sequence of consecutive indexes of the DVRBs canbe reversed by a block interleaver. Here, the sequence of consecutiveindexes means that the index number is sequentially incremented by onebeginning with 0. A sequence of indexes outputted from the blockinterleaver is sequentially mapped to a sequence of consecutive indexesof PRB1s (see FIG. 6). It is assumed that. the VRBs of FIG. 6 are allallocated as DVRBs. Thereafter, the sequence of indexes outputted fromthe block interleaver is cyclically Shifted by a predetermined numberand the cyclically shifted index sequence is sequentially mapped to asequence of consecutive indexes of PRB2s (see FIG. 7). It is assumedthat the VRBs of FIG. 7 are all allocated as DVRBs. In this manner, PRBindexes and DVRB indexes can be mapped over two slots.

On the other hand, in the above processes, a sequence of consecutiveindexes of the DVRBs, not passed through the interleaver, may besequentially mapped to the sequence of consecutive indexes of the PRB1s.Also, the sequence of consecutive indexes of the DVRBs, not passedthrough the interleaver, may be cyclically shifted by the predeterminednumber and the cyclically shifted index sequence may be sequentiallymapped to the sequence of consecutive indexes of the PRB2s.

According to the above-mentioned processes of mapping DVRBs to PRBs, aPRB1(i) and a PRB2(i) having the same index i can be mapped to aDVRB1(m) having an index ‘m’ and a DVRB2(n) having an index ‘n’,respectively. For example, referring to FIGS. 6 and 7, a PRB1(1) and aPRB2(1) are mapped to a DVRB 1(6) and a DVRB2(9) having differentindexes, respectively. A frequency diversity effect can be obtainedbased on the DVRB mapping scheme.

A variety of methods for allocating such VRBs may be used, for example,a bitmap method and a compact method. According to this bitmap method,resources can be freely allocated all over the system band, andnon-consecutive RBs can also be allocated. However, the above-mentionedbitmap method has a disadvantage in that it unavoidably increases thenumber of bits requested for allocation of RBs as the number of the RBsincreases. According to the compact method, only one set of consecutiveRBs can be assigned all over the system band. In order to represent theconsecutive RBs, a resource indication, value (RIV) may be defined. ThisRIV may represent a combination of a start point (S) of the series ofallocated RBs among all RBs and a length (L) of the series of allocatedRBs. According to the number of generable combinations of the startpoint (S) and the length (L), the number of bits representing a certainRIV for indicating a specific combination is decided by the abovecompact method. Assuming that the number of bits representing this RIVcan be reduced, the remaining bits may be used to transmit otherinformation.

SUMMARY OF THE INVENTION

An object of the present invention devised to solve the problem lies ona method for reducing an amount of control information representing arange of allocated resources in a resource allocation scheme based onthe compact method.

The object of the present invention can be achieved by providing, in awireless mobile communication system supporting a compact schedulingscheme, which supports a downlink control information format andallocates one set of consecutive virtual resource blocks (VRBs) to onecodeword, a method for detecting a resource indication value (RIV)indicating a start index (S) and length (L) of the one set ofconsecutive virtual resource blocks (VRBs) allocated by the compactscheduling scheme, the method including: receiving downlink controlinformation including resource block allocation information; and, if thedownlink control information format of the received downlink blockallocation information is used for the compact scheduling scheme,detecting the resource individual value (RIV) from the resource blockallocation information, wherein the start point (S) is any one ofelements of a first set {s: s=P+mT<N_(RB)} (where P is a predeterminedinteger of 0 or higher, T is a predetermined natural number, m is aninteger of 0 or higher, and N_(RB) is the number of resource blocks(RBs) available in the wireless mobile communication system), and thelength (L) is any one of elements of a second set {l: l=K+nG≦N_(RB)},(where K is a predetermined integer of 0 or higher, G is a predeterminednatural number, and n is a natural number).

N_(RB) may be limited to N_(VRB). N_(VRB) may be the number of virtualresource blocks (VRBs) available in the wireless mobile communicationsystem.

T may be equal to G.

P may be zero (P=0), and K may be zero (K=0).

N_(RB) may be denoted by N_(RB)=└N_(VRB)/G┘·G, where N_(VRB) is thenumber of virtual resource blocks (VRBs) available in the wirelessmobile communication system.

The l value may be equal to or less than a predetermined valueL^(limit), where L^(limit) may be equal to or higher than K and may belower than the N_(RB) value.

In another aspect of the present invention, there is provided, in awireless mobile communication system supporting the compact schedulingscheme, a method for detecting a resource indication value (RIV)indicating a start index (S) and length (L) of one set of consecutivevirtual resource blocks (VRBs) allocated by the compact schedulingscheme, the method including: receiving downlink control informationincluding resource block allocation information; and, if a downlinkcontrol information format of the received downlink control informationindicates the use of the compact scheduling scheme, detecting theresource indication value (RIV) from the resource block allocationinformation, wherein, if Y−1≦└X/2┘ is given, the resource indicationvalue (RIV) is denoted by RIV=X(Y−1)+Z, or else the resource indicationvalue (RIV) is denoted by RIV=X(X−Y+1)+(X−1−Z), where X is denoted byX=└N_(RB)/G┘, Y is denoted by Y=L/G, and Z is denoted by Z=S/G, inwhich, L is the length of the one set of the consecutive virtualresource blocks (VRBs), S is the start index of the one set of theconsecutive virtual resource blocks (VRBs), N_(VRB) is the number ofvirtual resource blocks (RBs) available in the wireless mobilecommunication system, each of L and S is a multiple of G, and G is apredetermined natural number.

N_(RB) may be denoted by N_(RB)=└N_(VRB)/G┘·G, where N_(VRB) is thenumber of virtual resource blocks (VRBs) available in the wirelessmobile communication system.

N_(bit) _(_) _(required) of a bit field used for transmitting theresource indication value (RIV) may be denoted by N_(bit) _(_)_(required)=┌log₂(RIV_(max)+1)┐, where RIV_(max) is denoted byRIV_(max)=└N_(RB)/G┘·(└N_(RB)/G┘+1)/2−1.

The present invention provides a radio resource scheduling scheme, astructure of scheduling information, and a transmission scheme, suchthat it can more efficiently implement a resource allocation scheme forcommon signaling.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention, illustrate embodiments of the inventionand together with the description serve to explain the principle of theinvention.

In the drawings:

FIG. 1 is a view showing an example of a radio frame structureapplicable to FDD.

FIG. 2 is a view showing an example of a radio frame structureapplicable to TDD.

FIG. 3 is a view showing an example of a resource grid structureconstituting a 3GPP transmission slot

FIG. 4A is a view showing an example of the structure of VRBs in onesubframe.

FIG. 4B is a view showing an example of the structure of PRBs in onesubframe.

FIG. 5 is a view illustrating an example of a method for mapping LVRBsto PRBs.

FIG. 6 is a view illustrating an example of a method for mapping DVRBsin a first slot to PRBs.

FIG. 7 is a view illustrating an example of a method for mapping DVRBsin a second slot to PRBs.

FIG. 8 is a view illustrating an example of a method for mapping DVRBsand LVRBs to PRBs.

FIG. 9 is a view illustrating an example of a method for allocatingresource blocks by a compact scheme.

FIG. 10 is a view illustrating an example of a method for mapping twoDVRBs having consecutive indexes to a plurality of contiguous PRBs.

FIG. 11 is a view illustrating an example of a method for mapping twoDVRBs having consecutive indexes to a plurality of spaced PRBs.

FIG. 12 is a view illustrating an example of RIVs when N_(RB)=20.

FIGS. 13 to 19 are views illustrating RIVs of generable combinations ofS and L values according to one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of thepresent invention with reference to the accompanying drawings. Thedetailed description, which will be given below with reference to theaccompanying drawings, is intended to explain exemplary embodiments ofthe present invention, rather than to show the only embodiments that canbe implemented according to the invention. The following detaileddescription includes specific details in order to provide a thoroughunderstanding of the present invention. However, it will be apparent tothose skilled in the art that the present invention may be practicedwithout such specific details. For example, the following descriptionwill be given centering around specific terms, but the present inventionis not limited thereto and any other terms may be used to represent thesame meanings. Also, wherever possible, the same reference numbers willbe used throughout the drawings to refer to the same or like parts.

Hereinafter, terms used in the detailed description of this applicationare defined as follows.

A ‘resource element (RE)’ represents a smallest frequency-time unit inwhich data or a modulated symbol of a control channel is mapped.Provided that a signal is transmitted in one OFDM symbol over Msubcarriers and N OFDM symbols are transmitted in one subframe. M×N REsare present in one subframe.

A ‘physical resource block (PRB)’ represents a unit frequency-timeresource for data transmission. In general, one PRB includes a pluralityof consecutive REs in a frequency-time domain, and a plurality of PRBsare defined in one subframe.

A ‘virtual resource block (VRB)’ represents a virtual unit resource fordata transmission. In general, the number of REs included in one VRB isequal to that of REs included in one PRB, and, when data is transmitted,one VRB can be mapped to one PRB or some areas of a plurality of PRBs.

A ‘localized virtual resource block (LVRB)’ is one type of the VRB. OneLVRB is mapped to one PRB, and PRBs to which different LVRBs are mappedare not duplicated. An LVRB may be interpreted just as a PRB.

A ‘distributed virtual resource block (DVRB)’ is another type of theVRB. One DVRB is mapped to some REs in a plurality of PRBs, and REs towhich different DVRBs are mapped are not duplicated.

‘N_(D)’=‘N_(d)’ represents the number of PRBs to which one DVRB ismapped. FIG. 8 illustrates an example of a method for mapping DVRBs andLVRBs to PRBs. In FIG. 8, N_(D)=3. As can be seen from FIG. 8, anarbitrary DVRB can be divided into three pars and the divided parts canbe mapped to different PRBs, respectively. At this time, the remainingpart of each PRB, not mapped by the arbitrary DVRB, is mapped to adivided part of another DVRB.

‘N_(PRB)’ represents the number of PRBs in a system. ‘N_(LVRB)’represents the number of LVRBs available in the system.

‘N_(LVRB)’ represents the number of LVRBs available in the system.

‘N_(DVRB)’ represents the number of DVRBs available in the system.

‘N_(LVRB) _(_) _(UE)’ represents the maximum number of LVRBs allocableto one user equipment (UE).

‘N_(DVRB) _(_) _(UE)’ represents the maximum number of DVRBs allocableto one UE.

‘N_(subset)’ represents the number of subsets.

Here, the “number of RBs” means the number of RBs divided on a frequencyaxis. That is, even in the case where RBs can be divided by slotsconstituting a subframe, the “number of RBs” means the number of RBsdivided on the frequency axis of the same slot.

FIG. 8 shows an example of definitions of LVRBs and DVRBs.

As can be seen from FIG. 8, each RE of one LVRB is one-to-one mapped toeach RE of one PRB. For example, one LVRB is mapped to a PRB0 (801). Incontrast, one DVRB is divided into three parts and the divided parts aremapped to different PRBs, respectively. For example, a DVRB0 is dividedinto three parts and the divided parts are mapped to a PRB1, PRB4 andPRB6, respectively. Likewise, a DVRB 1 and a DVRB2 are each divided intothree parts and the divided parts are mapped to the remaining resourcesof the PRB1, PRB4 and PRB6. Although each DVRB is divided into threeparts in this example, the present invention is not limited thereto. Forexample, each DVRB may be divided into two parts.

Downlink data transmission from a base station to a specific terminal oruplink data transmission from the specific terminal to the base stationis made through one or more VRBs in one subframe. When the base stationtransmits data to the specific terminal, it has to notify the terminalof which one of the VRBs through which the data will be transmitted.Also, in order to enable the specific terminal to transmit data, thebase station has to notify the terminal of which one of the VRBs throughwhich the data can be transmitted.

Data transmission schemes can be broadly classified into a frequencydiversity scheduling (EDS) scheme and a frequency selective scheduling(FSS) scheme. The FDS scheme is a scheme that obtains a receptionperformance gain. through frequency diversity, and the FSS scheme is ascheme that obtains a reception performance gain through frequencyselective scheduling.

In the FDS scheme, a transmission stage transmits one data packet oversubcarriers widely distributed in a system frequency domain so thatsymbols in the data packet can experience various radio channel fadings.Therefore, an improvement in reception performance is obtained bypreventing the entire data packet from being subject to unfavorablefading. In contrast, in the FSS scheme, an improvement in receptionperformance is obtained by transmitting the data packet over one or moreconsecutive frequency areas in the system frequency domain which are ina favorable fading state. In a cellular OFDM wireless packetcommunication system, a plurality of terminals are present in one cell.At this time, because the radio channel conditions of the respectiveterminals have different characteristics, it is necessary to performdata transmission of the PDS scheme with respect to a certain terminaland data transmission of the FSS scheme with respect to a differentterminal even within one subframe. As a result, a detailed FDStransmission scheme and a detailed FSS transmission scheme must bedesigned such that the two schemes can be efficiently multiplexed withinone subframe. On the other hand, in the FSS scheme, a gain can beobtained by selectively using a band favorable to a UE among allavailable bands. In contrast, in the FDS scheme, a comparison is notmade as to whether a specific band is good or bad, and, as long as afrequency interval capable of adequately obtaining a diversity ismaintained, there is no need to select and transmit a specific frequencyband. Accordingly, it is advantageous to an improvement in entire systemperformance to perform the frequency selective scheduling of the FSSscheme preferentially when scheduling.

In the FSS scheme, because data is transmitted using subcarriersconsecutively contiguous in the frequency domain, it is preferable thatthe data is transmitted using LVRBs. At this time, provided that N_(PRB)PRBs are present in one subframe and a maximum of N_(LVRB) LVRBs areavailable within the system, the base station can transmit bitmapinformation of N_(LVRB) bits to each terminal to notify the terminal ofwhich one of the LVRBs through which downlink data will be transmittedor which one of the LVRBs through which uplink data can be transmitted.That is, each bit of the N_(LVRB)-bit bitmap information, which istransmitted to each terminal as scheduling information, indicateswhether data will or can be transmitted through an LVRB corresponding tothis bit, among the N_(LVRB) LVRBs. This scheme is disadvantageous inthat, when the number N_(LVRB) becomes larger, the number of bits to betransmitted to each terminal becomes larger in proportion thereto.

On the other hand, a physical downlink control channel DCI (PDCCH)transferred to a user equipment (UE) may have a plurality of formats. Aresource allocation field transferred over the PDCCH may have differentstructures according to DCI formats. Thus, the user equipment (UE) mayinterpret the resource allocation field according to a format of thereceived DCI.

The resource allocation field may have two parts, i.e., resource blockallocation information and a resource allocation header field. Aplurality of resource allocation types may be defined. For example,according to a first-type resource allocation, the resource blockallocation information may have a bitmap indicating one set ofconsecutive physical resource blocks (PRBs). In this case, one bit maybe allocated to one resource block group (RBG). According to asecond-type resource allocation, resource block allocation informationmay have a bitmap indicating subsets or RBs allocated to the UE.According to a third-type resource allocation, resource block allocationinformation may have a bitmap indicating consecutively-allocated VRBs.At this time, the resource allocation field may include a resourceindication value (RIV) indicating a start resource block and the lengthof consecutively-allocated resource blocks (RBs). Examples of theabove-mentioned resource allocation types have been disclosed in the3GPP TS 36.213 document

For example, a DCI format 1A prescribed in the 3GPP TS 36.213 may beused for compact scheduling of one physical downlink shared channel(PDSCH) codeword. This compact scheduling is a scheduling scheme forallocating one set of consecutive VRBs to a user equipment (UE), andcorresponds to the above third-type resource allocation. Hereinafter,the above-mentioned compact scheduling in the present invention may bereferred to as a compact scheme.

As described above, provided that a terminal (i.e., the UE) may beassigned only one set of contiguous RBs, information of the assigned RBsmay be represented by the compact scheme denoted by both a start pointof RBs and the number of the RBs.

FIG. 9 is a view illustrating an example of a method for allocatingresource blocks by a compact scheme. If the number of available RBs isdenoted by N_(RB)=N_(VRB), the length of available RBs is differentdepending on respective start points as shown in FIG. 9, such that thenumber of combinations for RB allocation is N_(LVRB)(N_(LVRB)+1)/2 inthe end. Accordingly, the number of hits required for the combinationsis ‘ceiling(log2(N_(LVRB)(N_(LVRB)+1)/2))’. Here, ceiling “x” meansrounding “x” up to a nearest integer. This method is advantageous overthe bitmap scheme in that the number of bits does not so significantlyincrease with the increase in the number N_(LVRB).

On the other hand, for a method for notifying a user equipment (UE) ofDVRB allocation, it is necessary to previously promise the positions ofrespective divided parts of DVRBs distributively transmitted for adiversity gain. Alternatively, additional information may be required todirectly notify the positions. Preferably, provided that the number ofbits for signaling for the DVRBs is set to be equal to the number ofbits in LVRB transmission of the above-stated compact scheme, it ispossible to simplify a signaling bit format in a downlink. As a result,there are advantages that the same channel coding can be used, etc.

Here, in the case where one UE is allocated a plurality of DVRBs, thisUE is notified of a DVRB index of a start point of the DVRBs, a length(=the number of the allocated DVRBs), and a relative position differencebetween divided parts of each DVRB (e.g., a gap between the dividedparts).

FIG. 10 illustrates an example of a method for mapping two DVRBs havingconsecutive indexes to a plurality of contiguous PRBs.

As shown in FIG. 10, in the case where a plurality of DVRBs havingconsecutive indexes are mapped to a plurality of contiguous PRBs, firstdivided parts 1001 and 1002 and second divided parts 1003 and 1004 arespaced part from each other by a gap 1005, while divided parts belongingto each of the upper divided parts and lower divided parts arecontiguous to each other, so that the diversity order becomes 2.

FIG. 11 illustrates an example of a method for mapping two DVRBs havingconsecutive indexes to a plurality of spaced PRBs.

In the method of FIG. 11, DVRB indexes are constructed as shown inFIG. 1. When allowing DVRBs to correspond to PRBs, consecutive DVRBindexes can be allowed to be distributed, not correspond to contiguousPRBs. For example, a DVRB index ‘0’ and a DVRB index ‘1’ are notarranged contiguous to each other. In other words, in FIG. 11, DVRBindexes are arranged in the order of 0, 8, 16, 4, 12, 20, . . . , andthis arrangement can be obtained by inputting the consecutive indexes inFIG. 10 to, for example, a block interleaver. In this case, it ispossible to obtain distribution within each of divided parts 1101 and1102, as well as distribution by a gap 1103. Therefore, when a UE isallocated two DVRBs as shown in FIG. 11, the diversity order increasesto 4, resulting in an advantage that the diversity gain can be obtainedstill more.

At this time, the value of the gap indicative of the relative positiondifference between the divided parts can be expressed in two ways.Firstly, the gap value can be expressed by a difference between DVRBindexes. Secondly, the gap value can be expressed by a differencebetween indexes of PRBs to which a DVRB is mapped. In the case of FIG.11, Gap=1 in the first way, while Gap=3 in the second way. FIG. 12 showsthe latter case 1103. Meanwhile, if the total number of RBs of thesystem is changed, the DVRB index arrangement may be changedaccordingly. In this case, the use of the second way has the advantageof grasping a physical distance between the divided parts.

In order to perform signaling of DVRB allocation, the above-mentionedLVRB compact scheme may be used. In this case, a start point ofconsecutively-allocated RBs and length information of the RBs correspondto a start point of VRB indexes instead of PRB indexes and lengthinformation of them, respectively.

As described above, in the compact scheme, LVRB signaling includes astart point of RBs and length information of the RBs. In order toperform the DVRB signaling, gap information may be additionally requiredin some cases. In order to constantly maintain the number of bitsrequired for the entire signaling, there is a need to limit the lengthinformation such that an amount of information must be reduced. Forexample, in case of using 50 RBs or more, one bit of the RIV field mustbe assigned for gap indication, such that there is a need to reduce thenumber of bits required for transferring the RIV with the limitation inthe length information.

On the other hand, in case of using RBs to perform the common signalingfor several users, a control signaling for notifying allocated RBs mustallow all users present in a cell to read information of the allocatedRBs. Thus, for this control signaling, a code rate may be reduced or atransmission power may be increased, such that the resultant controlsignaling information having a low code rate and a high transmissionpower may be transferred to several users. In order to reduce the coderate of the control signaling to which limited resources are allocated,an amount of control data must be reduced. In order to reduce the amountof control data, the number of bits required for RB allocationinformation must be reduced.

Likewise, control message data transferred to allocated RBs must allowall users present in the cell to read corresponding information, suchthat the control message data is transferred at a low code rate.Assuming that the code rate is 1/20, if an amount of data increases by16 bits, an amount of codeword made after a channel coding increases by320 bits.

In the 3GPP Long Term Evolution (CUE), assuming that one TX antennatransmission (i.e., 1 Tx antenna transmission) is carried out and oneOFDM symbol is used for a control signal, the number of symbols capableof transferring payload data within one RB (i.e., 1 RB) is 148. Thus,assuming that a quadrature phase shift keying (QPSK) modulation is used,the number of transferable bits is 296. As a result, data increases by16 bits, data of 320 bits increases, such that two RBs are additionallyneeded.

That is, in order to maintain a low code rate, although the size of dataincreases a little, the number of RBs required for transferring thisdata greatly increases, such that the necessity for RBs to be allocatedwith a granularity of one RB unit (i.e., a 1 RB-based granularity).

Hereinafter, a resource allocation signaling structure for establishinga step for limiting a start position with a granularity of one-RBallocation (i.e., 1 RB allocation) will be described in detail.

The following equation 1 shows an exemplary signaling method based onthe compact scheme which notifies a start point (S) of RBs and thenumber (=Length, L) of allocated RBs.

In the following description, “mod(x,y)” means “x mod y”, and “mod”means a modulo operation. Also, “└.┘” means a descending operation, andrepresents a largest one of integers equal to or smaller than a numeralindicated in “└┘”. On the other hand, “┌.┐” means an ascendingoperation, and represents a smallest one of integers equal to or largerthan a numeral indicated in “┌┐”. Also. “round(.)” represents an integernearest to a numeral indicated in “( )”. “min(x,y)” represents a smallervalue selected between x and y, whereas “max(x,y)” represents a largervalue selected between x and y.

if L − 1 ≦ └N_(RB)/2┘ then [Equation 1]   RIV = N_(RB)(L − 1) + S else  RIV = N_(RB)(N_(RB) − L + 1) + (N_(RB) − 1 − S) End Required bits N_(bit)_required = ┌log₂(RIV_(max) + 1)┐  Without limitation  RIV_(max) = N_(RB) · (N_(RB) + 1)/2 − 1   With limitation L^(Limit)  RIV_(max) = min{N_(RB) · (N_(RB) + 1)/2 − 1, N_(RB)(L^(linit) − 1) +N_(RB) − L^(linit) }

Assuming that the total number of all available RBs is denoted by N_(BB)and the beginning number of indexes to be assigned to the RBs is set to0, indexes from 0 to N_(RB)−1 are sequentially assigned to the RBs. Inthis case, N_(RB) may be the total number of all RBs contained in asystem band, the number of all RBs used as VRBs, or the number of RBscontained in any limited area.

Thus, the range of S may be 0≦S≦N_(RB)−1, and the range of allocable ‘L’value is changed according to this S value. In another view, the L valueis in the range of 1≦L≦N_(RB), and the range of available S value ischanged according to the L value. Namely, a certain S value is unable tobe combined with a specific L value.

A maximum value of each of the S and L values may be represented by abinary number, regardless of such impossible combinations. A bit fieldfor this binary number may be constructed for each of the S and Lvalues. In case of transmitting each of the bit fields, if N_(RB) is 20(i.e., N_(RB)=20), 20 is less than 2⁵(i.e., 20<2⁵), so that 5 bits forthe S value and 5 bits for the L values, namely, a total of 10 bits, areneeded. However, overhead of unnecessary transmission bits is generatedbecause these 10 bits include even information of useless combinationsincapable of being actually generated. Thus, if each generablecombination of S and L values is represented by ‘RIV’, this RIV isconverted into a binary number according to binary representation, andthe resultant RIV of the binary number is then transferred, the numberof transmission bits can be reduced.

FIG. 12 is a view illustrating an example of RIVs when N_(RB)=20.

As can be seen from FIG. 12, ‘RIV’ is decided according to S and Lvalues. In case of calculating ‘RIV’ related to 0≦S≦N_(RB)−1 in each ofall L values using Equation 1, RIV's of FIG. 12 are made. The value ofeach element shown in FIG. 12 is ‘RIV’ indicating a combination of S andL values corresponding to the above element. Values contained in a leftupper part covering the almost half of FIG. 12 correspond to generablecombinations of S and L values when N_(RB)=20, and values contained in aright lower part colored in gray, covering the other half of FIG. 12,correspond to combinations of S and L values incapable of beinggenerated.

In this scheme, RIVs present in the gray-colored part under thecondition of L−1≦└N_(RB)/2┘, are mapped to RIVs under the othercondition of L−1>└N_(RB)/2┘, such that there are no RIVs to be wasted.For example, if N_(RB) is set to 20 (i.e., N_(RB)=20), RIVs present in aspecific pan corresponding to L<└N_(RB)/2┘+1=└20/2┘+1=11 among the rightlower part of FIG. 12 are reused in another part corresponding toL>└N_(RB)/2┘+1=└20/2┘+1=11 among the left upper part of FIG. 12. In thiscase, a maximum value (i.e., a maximum RIV) among RIVs present in theleft upper end is 209.

In this scheme, the maximum RIV may influence the number of transmissionbits, RIVs below the maximum RIV may not be mapped to values incapableof being obtained by combinations of actual S and L values. That is, allvalues below the maximum RIV correspond to generable combinations of Sand L values.

In case of separately transmitting the S value, a maximum S value is 19,such that 5 bits are needed to indicate this S value ‘19’ (where0≦19<2⁵) In case of separately transmitting the L value, a maximum Lvalue is 20, such that 5 bits are needed to indicate this L value ‘20’(where 0≦20<2⁵). Therefore, in case of transmitting the S and L valuesindependent of each other, 10 bits are needed in the end. However, theRIVs are in the range of 0≦RIV≦209<2⁸, such that 8 bits are needed toindicate these RIVs, as denoted by N_(bit) _(_) _(required)=8. As aresult, it can be recognized that 2 bits are saved as compared to theabove case of transmitting the S and L values independent of each other.

In the meantime, in the above-mentioned RIV construction method, if amaximum value (=L^(limit)) of allocable RBs is limited, i.e., if the Lvalue is limited to L^(limit) or less, the number of required bits maybe reduced.

In FIG. 12, if L^(limit) is set to 6 (i.e., L^(limit)=6), the range ofgenerable L values is given as 1≦L≦6, combinations having other L valueshaving the range of 7≦L≦20 are not in use. At this time, it can berecognized that a maximum RIV among RIVs is 114. That is, the range ofgenerable RIVs is given as 0≦RIV≦114<2⁷, so that the number of requiredbits is 7 as denoted by N_(bit) _(_) _(required) _(_) _(lim)=7.

However, in case of using RBs for the common signalling as describedabove, there is a need to reduce the number of bits used for resourceallocation. Thus, a method for limiting the S and L values according tothe present invention will hereinafter be described in detail.

Embodiment 1

A method for limiting each of S and L values to a multiple of G (where Gis a positive integer) according to a first embodiment of the presentinvention will hereinafter be described.

If each of the S and L values is limited to a multiple of G, a maximumRIV among RIVs represented by combinations of S and L values can belowered. That is, an incremental step of the S value may be set to G andan incremental granularity of the L value may be established in units ofG.

FIG. 13 shows RIVs related to generable combinations of S and L valuesunder the condition that N_(RB) is 20 (N_(RB)=20) and G is 2 (G=2)according to the first embodiment.

A gray-colored area of FIG. 13 corresponds to combinations of S and Lvalues incapable of being generated under the condition that N_(RB) is20 (N_(RB)=20) and G is 2 (G=2). The RIVs are in the range of0≦RIV≦54<2⁶, such that 6 bits are needed to indicate these RIVs, asdenoted by N_(compact) _(_) _(bit)=6.

If a step of the start point and its granularity are all set to G, thenumber of bits used for expressing RIVs becomes lower than that of theconventional scheme.

In this way, provided that L^(limit) may be fixed to limit a maximumvalue among available L values, the number of required bits may befurther reduced. As can be seen from FIG. 13, if L^(limit) is set to 6,it can be recognized that a maximum RIV is 27. At this time, becausecombinations each having the L value within the range of 8≦L≦20 are notin use, RIVs are in the range of 0≦RIV≦27<2⁵, such that the number ofrequired bits is 5 as denoted by N_(bit) _(_) _(required) _(_) _(lim)=5.

The following equation 2 is used to obtain RIVs according to S and Lvalues under the condition that N_(RB) and G are given. In this case,the number of bits required for expressing the RIVs may be calculated indifferent ways according to the setting of L^(limit). If a maximumlength of RBs is needed, L^(limit) is denoted by L^(limit)=G·┌L^(max)^(_) ^(required)/G┐. If a maximum allowable amount of RBs is given,L^(limit) is denoted by L^(limit)=G·└L^(max) ^(_) ^(allowed)/G┘.

<T=G> [Equation 2] Step: T=G RBs Granularity: G RBs  if (L/G − 1) ≦└└N_(RB)/G┘/2┘ then   RIV = └N_(RB)/G┘ · (L/G − 1) + S/G  else   RIV =└N_(RB)/G┘ · (└N_(RB)/G┘ − L/G + 1) + (└N_(RB)/G┘ − 1 − S/G)  endRequired bits   N_(bit) _required = ┌log₂(RIV_(max) + 1)┐  Withoutlimitation   RIV_(max) = └N_(RB)/G┘ · (└N_(RB)/G┘ + 1)/2 − 1  Withlimitation L^(Linit) = G · ┌L^(max)_required/G┐ or G ·└L^(max)_allowed/G┘  RIV_(max) = min(└N_(RB)/G┘(L^(limit)/G −1) +└N_(RB)/G┘ − L^(limit)/G, └N_(RB)/G┘ · (└N_(RB)/G┘ + 1)/2 − 1} }

As can be seen from Equation 2, parameters of equations constructing theabove Equation 1 are substituted into others in Equation 2, such thatthere is an advantage in that the existing equation can be used withoutany change. In more detail, Equation 1 showing a method for deciding astart point and a length on a basis of one RB may correspond to thefollowing equation 3 under the condition that X=N_(RB), Y=L, and Z=S.Equation 2 showing a method for deciding a start point and a length inunits of G RBs may correspond to the following equation 3 under thecondition that X=└N_(RB)/G┘, Y=L/G, and Z=S/G.

  if Y − 1 ≦ └X/2┘ [Equation 3]  RIV = X(Y − 1) + Z else  RIV = X(X −Y + 1) + (X − 1 − Z) End

This relationship may also be represented by the following expression 1.

  Method of deciding Start Point and Length in units of one RB (1 RB) X= N_(RB), Y = L, Z = S [Expression 1] if Y − 1 ≦ └X/2┘  RIV = X(Y − 1) +Z else  RIV = X(X − Y + 1) + (X − 1 − Z) End Method of deciding startpoint and length in units of G RBs X = └N_(RB)/G┘, Y = L/G, Z = S/G if Y− 1 ≦ └X/2┘  RIV = Z(Y − 1) + Z else  RIV = X (X − Y + 1) + (X − 1 − Z)End

On the other hand, assuming that N_(RB) is a multiple of G, each RIVobtained by the above equation which has been made to calculate RIVsusing combinations of S and L values in units of one RB (1 RB) isdivided by 0, such that the resultant RIV obtained by this divisionbecomes any one of RIVs obtained by combinations of S and L values inunits of G RBs, Therefore, assuming that N_(RB) is a multiple of G, theRIV may be represented by the following expression 2.

  Method for deciding Start Point and Length in units of G RBs in casethat N_(RB) is a multiple of G if L − 1 ≦ └N_(RB)/2┘ then [Expression 2] RIV' = N_(RB)(L − 1) + S else  RIV' = N_(RB)(N_(RB) − L + 1) + (N_(RB)− 1 − S) End RIV = RIV'/G

If the total number of all RBs of the system is set to N_(PRB), N_(VRB)indicating the number of VRBs used for allocating RB indexes or RBnumbers may be equal to or less than N_(PRB). Because each of allocatedRB indexes according to the method of Equation 2 proposed by the presentinvention is a multiple of G, the number of RBs used for this allocationmay also be denoted by a multiple of G. Thus, if N_(RB) for use in theabove expression is not a multiple of G, RBs as many as a remainder madewhen N_(RB) is divided by G may not be used for RB allocation.Therefore, it is preferable that N_(RB) be set to N_(RB)=└N_(VRB)/G┘·G.Under this condition denoted by N_(RB)=└N_(VRB)/G┘·G, it can berecognized that X=└N_(RB)/G┘=└└N_(VRB)/G┘·G/G┘=└└N_(VRB)/G┘┘=└N_(VRB)/G┘is made.

Assuming that the number of actually available RBs is N_(VRB), due togranularity restriction, RBs as many as a remainder made when N_(VRB) isdivided by G, i.e., N_(RB) ^(remain)=N_(VRB)−└N_(VRB)/G┘·G remainingRBs, may not be allocated.

In order to allocate such remaining RBs, N_(RB) may be set toN_(RB)=┌N_(VRB)/G┐·G. However, under this conditionN_(RB)=┌N_(VRB)/G┐·G, if the remaining RBs are allocated, the L valuemay include the number of imaginary RBs, i.e., N_(RB)^(imaginary)=┌N_(VRB)/G┐·G−N_(VRB). As a result, if the remaining RBsare allocated, the length of actually-allocated RBs becomes L−N_(RB)^(imaginary).

Embodiment 2

According to this embodiment, an optimization method, under thecondition that each of S and L values is limited to a multiple of G(where G is a positive integer) and L^(limit) is established, willhereinafter be described in detail.

FIG. 14 shows RIVs related to generable combinations of S and L valuesunder the condition that N_(RB) is 40 (N_(RB)=40) and G is 2 (G=2) inthe method disclosed in the first embodiment. In this case, it can berecognized that a maximum RIV among RIVs on the condition that L^(limit)is 14 (i.e., L^(limit)=14) is 133.

If L^(limit) is set to 14 (L^(limit)=14), 8 bits are needed due to0≦RIV≦133<2⁸. However, RIVs (=39, 58˜59, 77˜79, 96˜99, 115˜119) includedin the gray-colored part (see FIG. 14) under the condition 4≦L≦12 maynot be used as RIVs although the RIVs (=39, 58˜59, 77˜79, 96˜99,115˜119) are less than the maximum RIV 133. That is, the number of bitsrequired for transmitting RIVs may be wasted. In order to remove thewasted RIVs, under the condition that N_(RB), G and L^(limit) arelimited, there is a need to construct a table for RIVs such that allnumbers below the maximum RIV among RIVs corresponding to combinationsof S and L values can be actually available. That is, all RIVs in therange from 0 to the maximum RIV must represent combinations ofactually-generable S and L values.

FIG. 15 shows RIVs related to generable combinations of S and L valuesunder the condition that N_(RB) is 40 (N_(RB)=40), G is 2 (G=2), andL^(limit) is 14 (L^(limit)=14) according to the second embodiment.

Due to 0≦RIV=118<2⁷, the number of required hits N_(bit) _(_)_(required) _(_) _(lim) is 7. In this case, it can be recognized thatbits for representing generable combinations of S and L values are notwasted because RIVs included in the gray-colored part having L values inthe range of 2≦L≦6 are used in generable combinations of S and L valuesunder the condition 10≦L≦14. Thus, compared with the method of FIG. 14,signaling overhead is reduced by one bit when performing signaling ofthe same RB-allocation combinations as those of FIG. 14.

The following equation 4 is used to obtain RIVs using combinations of Sand L values under the condition that N_(RB), G and L^(limit) are givenin the method of FIG. 15. In this case, the number of required bits mayalso be calculated by equations included in Equation 4. If a maximumlength of RBs is limited, L^(limit) is denoted by L^(limit)=G·┌L^(max)^(_) ^(required)/G┐. If a maximum allowable amount of RBs is given,L^(limit) is denoted by L^(Limit)=G·└L^(max) ^(_) ^(allowed)/G┘.

<T=G, Optimized for limitation L^(Limit) > [Equation 4] Step: T=G RBsGranularity: G RBs Optimized for limitation L^(linit) = G ·┌L^(max)_required/G┐ or G · ┌L^(max)_allowed/G┐ if L/G ≦ ┌L^(linit)/G/2┐then  RIV = (2 · └N_(RB)/G┘ − L^(linit)/G + 1)(L /G − 1) + S/G else  RIV= (2 · └N_(RB)/G┘ − L^(linit)/G + 1)(L^(linit)/G − L /G + 1) − (1 + S/G)end Required bits if L^(linit)/G/2 ≦ ┌L^(linit)/G/2┐ then  RIV_(max) =(2 · └N_(RB)/G┘ − L^(linit)/G + 1)(L^(RIVmax)/G − 1) + └(N_(RB) −L^(RIVmax))/G┘ else  RIV_(max) = (2 · └N_(RB)/G┘ − L^(limit)/G +1)(L^(RIVmax)/G) − 1 end where L^(RIVmax) = min(G · ┌N_(RB)/G/2┐,·L^(linit)

Assuming that the number of actually available RBs is N_(VRB), due tothe granularity restriction, RBs as many as a remainder made whenN_(VRB) is divided by G, i.e., N_(RB) ^(remain)=N_(VRB)−└N_(VRB)/G┘·Gremaining RBs, may not be allocated. In order to allocate such remainingRBs, N_(RB)may be set to N_(RB)=┌N_(VRB)/G┘·G. However, under thiscondition N_(RB)=┌N_(VRB)/G┐·G, if the remaining RBs are contained andallocated, the L value may include the number of imaginary RBs, i.e.,N_(RB) ^(imaginary)=┌N_(VRB)/G┐·G−N_(VRB). As a result, if the remainingRBs are contained and allocated, the length of actually-allocated RBs isdenoted by L−N_(RB) ^(imaginary).

Embodiment 3

According to a third embodiment, a method of constructing an optimumtable of RIVs, under the condition that S is limited to a multiple of T(where T is a positive integer) and L is limited to a multiple of G(where G is a positive integer), will hereinafter be described indetail.

In the above-mentioned first embodiment, it is assumed that the positionof a start point of allocated RBs and the length of the RBs are eachlimited to a multiple of G (where G is a positive integer). However, inthe third embodiment, the start point is limited to one of multiples ofa first positive integer, and the length is limited to one of multiplesof a second positive integer which is independent from the firstpositive integer, respectively. That is, S is limited to a multiple ofT, and L is limited to a multiple of G.

FIG. 16 shows RIVs related to generable combinations of S and L valuesunder the condition that N_(RB) is 20 (N_(RB)=20), S is a multiple ofT(=4), and L is a multiple of G(=2) according to the third embodiment.

FIG. 17 shows RIVs related to generable combinations of S and L valuesunder the condition that N_(RB) is 20 (N_(RB)=20), S is a multiple ofT(=2), and L is a multiple of G(=4) according to the third embodiment.

In FIGS. 16 and 17, the gray-colored parts correspond to combinations ofS and values incapable of being generated under N_(RB)=20.

T=2 and G=4, RIVs are in the range of 0≦RIV≦26<2⁵, such that 5 bits areneeded to represent these RIVs, as denoted by N_(bit) _(_)_(required)=5. In this case, if L^(limit) is set to 8 (L^(limit)=8),RIVs are in the range of 0≦RIV≦15<2⁴, such that 4 bits are needed torepresent these RIVs, as denoted by N_(bit) _(_) _(required) _(_)_(lim)=4.

If T=4 and G=2, RIVs are in the range of 0≦RIV≦29<2⁵, such that 5 bitsare needed to represent these RIVs, as denoted by N_(bit) _(_)_(required)=5. In this case, if L^(limit) is set to 8 (L^(limit)=8),RIVs are in the range of 0≦RIV≦18<2⁵, such that 5 bits are needed torepresent these RIVs, as denoted by N_(bit) _(_) _(required) _(_)_(lim)=5.

The following equation 5 is made to calculate RIVs using combinations ofS and L values under the condition that N_(RB), T, and G are given. Inthis case, the number of required bits may be calculated in differentways according to L^(limit). Under this condition, it is assumed that Tor G is an integer multiple of min(T, G). If the maximum length of RBsis limited, L^(limit) is denoted by L^(limit)=G·┌L^(max) ^(_)^(required)/G┐. A maximum allowable amount of RBs is given, L^(limit) isdenoted by L^(limit)=G·└L^(max) ^(_) ^(allowed)/G┘.

< T and G are Independent > [Equation 5] Step: T RBs Granularity: G RBsif (L /G − 1) ≦ └N_(RB)/G/2 + mod(└N_(RB)/G┘ − 1,T/G)/2┐ then   RIV =┌(N_(RB) − G + 1)/T┐ (L /G − 1) + S/T else   RIV = ┌(N_(RB) − G + 1)/T┐(└N_(RB)/G┘ − L /G + 1 + mod(└N_(RB)/G┘ − 1,T/G))     + (┌(N_(RB) − G +1)/T┐ − 1 − S/T) end Required bits N_(bit)_required = ┌log₂(RIV_(max) +1)┐ if (L^(RIVmax)/G − 1) ≦ ┌N_(RB)/2/G + mod(└N_(RB)/G┘ − 1,T/G)/2┘then   RIV_(max) = ┌(N_(RB) − G + 1)/T┐(L^(RIVmax)/G − 1) + S^(RIVmax)/Telse   RIV_(max) ┌(N_(RB) − G + 1)/T┐(L^(RIVmax)/G − 1) − 1 end where,S^(RIVmax) = └(N_(RB) − L^(RIVmax))/T┘T  Without limitation  L^(RIVmax)= G · [round(N_(RB)/2/G + mod(└N_(RB)/G┘ − 1,T/G)/2) + 1]  Withlimitation L^(linit) = G · ┌L^(max)_required/G┐ or G ·└L^(max)_allowed/G┘  L^(RIVmax) = min(G · [round(N_(RB)/2/G + mod(└N_(RB)/G┘ − 1,T/G)/2) + 1] , L^(linit))

Assuming that the number of actually available RBs is N_(VRB), some RBshaving large indexes may not be allocated due to the granularityrestriction. In order to allocate such remaining RBs, N_(RB) may be setto N_(RB)=┌N_(VRB)/max(T,G)┐·max(T, G). However, under this condition,if the remaining RBs are allocated, the L value may include the numberof imaginary RBs, i.e, N_(RB) ^(imaginary)=S+L−N_(VRB). As a result, ifthe remaining RBs are allocated, the length of actually-allocated RBs isdenoted by L−N_(RB) ^(imaginary)=N_(VRB)−S.

Embodiment 4

According to a fourth embodiment, an optimization method, under thecondition that S starts from P and then increases by a multiple of G,and L starts from K and then increases by a multiple of G, willhereinafter be described in detail.

In the first embodiment, it is assumed that the position of a startpoint of allocated RBs and the length of the RBs are each limited to amultiple of G (where G is a positive integer). In other words, the firstembodiment assumes that the start point S of RBs start from 0 and thenincreases by G, and the length L of RBs starts from 1 and then increasesby G.

The following fourth embodiment relates to a method for constructingRIVs under the condition that the start point S of RBs starts from anoffset P and then increases by G, and the length L of RBs starts fromanother offset K and then increases by G. That is, this fourthembodiment relates to a method for constructing RIVs under S∈{P, P+G,P+2G, P+3G, . . .} and L∈{K, K+G, K+2G, K+3G, . . . }.

FIG. 18 shows RIVs related to generable combinations of S and L valueswhen N_(RB)=20, G=2, P=1, and K=4 according to the fourth embodiment.The gray-colored part of FIG. 18 corresponds to combinations of S and Lvalues incapable of being actually generated when N_(RB)=20. RIVs are inthe range of 0≦RIV≦35<2⁶, such that 6 bits are needed to represent theseRIVs.

If the range of available L values is limited by establishment ofL^(limit), the number of required bits may be reduced. Referring to FIG.18, if L^(limit) is set to 8 (L^(limit)=8), it can be recognized that amaximum RIV among RIVs is 21. In this case, because combinations havingL values in the range of 10≦L≦18 may not be used, the range of RIVs maybe 0≦RIV≦21<2⁵, such that 5 bits are needed to represent these RIVs asdenoted by ‘N_(bit) _(_) _(required) _(_) _(lim)=5’.

The following equation 6 is made to calculate RIVs using combinations ofS and L values under the condition that N_(RB), T, and G are given.Under this condition, it is assumed that T or G is an integer multipleof min(T, G). If the length of RBs is limited, L^(limit) is denoted byL^(limit)=G·┌(L^(max) ^(_) ^(required)−K)/G┐°K. If a maximum allowableamount of RBs is given, L^(limit) is denoted by L^(Limit)=G·└(L^(max)^(_) ^(allowed)K)/G┘+K.

$\begin{matrix}{{{{{< T} = {G\mspace{14mu}{starting}\mspace{14mu}{from}\mspace{14mu}{offset}\mspace{14mu} P\mspace{14mu}{and}\mspace{14mu} K}},{{{respectively} > {{Step}\text{:}\mspace{14mu} T}} = {G\mspace{14mu}{RBs}\mspace{14mu}{starting}\mspace{14mu}{from}\mspace{14mu} P}}}{Granularity}\text{:}\mspace{14mu} G\mspace{14mu}{RBs}\mspace{14mu}{starting}\mspace{14mu}{from}\mspace{14mu} K}\mspace{31mu}{{{if}\mspace{14mu}\left( {L - K} \right)\text{/}G} \leq {\left\lfloor {\left\lfloor {{\left( {N_{RB} - P - K} \right)\text{/}G} + 1} \right\rfloor\text{/}2} \right\rfloor\mspace{14mu}{then}}}\mspace{59mu}{{RIV} = {{{\left\lfloor {{\left( {N_{RB} - P - K} \right)\text{/}G} + 1} \right\rfloor \cdot \left( {L - K} \right)}\text{/}G} + {\left( {S - P} \right)\text{/}G}}}\mspace{31mu}{else}\mspace{59mu}{{RIV} = {{\left\lfloor {{\left( {N_{RB} - P - K} \right)\text{/}G} + 1} \right\rfloor \cdot \left( {\left\lfloor {{\left( {N_{RB} - P - K} \right)\text{/}G} + 1} \right\rfloor - {\left( {L - K} \right)\text{/}G}} \right)} + \mspace{59mu}\left( {\left\lfloor {{\left( {N_{RB} - P - K} \right)\text{/}G} + 1} \right\rfloor - 1 - {\left( {S - P} \right)\text{/}G}} \right)}}\mspace{31mu}{end}{{Required}\mspace{14mu}{bits}}{N_{{bit}_{—}{required}} = \left\lceil {\log_{2}\left( {{RIV}_{\max} + 1} \right)} \right\rceil}\mspace{31mu}{{Without}\mspace{14mu}{limitation}}\mspace{31mu}{{RIV}_{\max} = {{{\left\lfloor {{\left( {N_{RB} - P - K} \right)\text{/}G} + 1} \right\rfloor \cdot \left\{ {\left\lfloor {{\left( {N_{RB} - P - K} \right)\text{/}G} + 1} \right\rfloor + 1} \right)}\text{/}2} - 1}}\mspace{31mu}{{With}\mspace{14mu}{limitation}}\mspace{31mu}{L^{linit} = {{G \cdot \left\lceil {\left( {L^{\max_{—}{required}} - K} \right)\text{/}G} \right\rceil} + {K\mspace{14mu}{or}\mspace{14mu}{G \cdot \left\lfloor {\left( {L^{\max_{—}{allowed}}K} \right)\text{/}G} \right\rfloor}} + K}}\mspace{31mu}{{RIV}_{\max} = {\min\begin{Bmatrix}{{{{\left\lfloor {{\left( {N_{RB} - P - K} \right)\text{/}G} + 1} \right\rfloor \cdot \left( {L_{linit} - K} \right)}\text{/}G} + \left\lfloor {\left( {N_{RB} - L^{linit} - P} \right)\text{/}G} \right\rfloor},} \\{{{\left\lfloor {{\left( {N_{RB} - P - K} \right)\text{/}G} + 1} \right\rfloor \cdot \left( {\left\lfloor {{\left( {N_{RB} - P - K} \right)\text{/}G} + 1} \right\rfloor + 1} \right)}\text{/}2} - 1}\end{Bmatrix}}}} & \left\lbrack {{Equation}\mspace{14mu} 6} \right\rbrack\end{matrix}$

On the other hand, parameters of equations constructing the aboveEquation 1 are substituted into others in Equation 6, such that Equation6 has an advantage in that it can use the existing equation without anychange. In more detail, Equation 1 showing the method for deciding thestart point and the length on a basis of one RB may correspond toEquation 3 under the condition that X=N_(RB), Y=L, and Z=S. Equation 6shows the method for controlling the start point of RBs to start from Pand then increase in units of G, and controlling the length of RBs tostart from K and then increase in units of G. This Equation 6 maycorrespond to Equation 3 under the condition that X=└(N_(RB)−P−K)/G┘,Y−1=(L−K)/G, and Z=(S−P)/G.

This relationship may also be represented by the following expression.

  Method of deciding Start Point and Length in units of one RB X =N_(RB), Y = L, Z = S [Expression] if Y − 1 ≦ └X/2┘  RIV = X(Y − 1) + Zelse  RIV = X(X − Y + 1) + (X − 1 − Z) End Method of controlling StartPoint of RBs to start from P and then increase in units of G, andcontrolling Length of RBs to start from K and then increase in units ofG X = └(N_(RB) − P − K)/G┘, Y − 1 = (L − K)/G, Z = (S − P)/G if Y − 1 ≦└X/2┘  RIV = X(Y − 1) + Z else  RIV = X(X − Y + 1) + (X − 1 − Z) end

Assuming that the number of actually available RBs is N_(VRB), due togranularity restriction, RBs as many as a remainder made when N_(VRB) isdivided by G, i.e., N_(RB) ^(remain)→└(N_(VRB)−K−P)/G┘·G+K+P−N_(VRB)remaining RBs, may not be allocated.

In order to allocate such remaining RBs, N_(RB) may be set toN_(RB)=┌(N_(VRB)−K−P)/G┐·G+K+P. However, under this condition, if theremaining RBs are allocated, the L value may include the number ofimaginary RBs, i.e., N_(RB) ^(imaginary)=┌(N_(VRB)−K−)/G┐·G+K+P−N_(VRB).As a result, if the remaining RBs are allocated, the length ofactually-allocated RBs is denoted by L−N_(RB) ^(imaginary).

Embodiment 5

According to a fifth embodiment, an optimization method, under thecondition that S starts from P and then increases by a multiple of T,and L starts from K and then increases by a multiple of G, willhereinafter be described in detail.

As can be seen from the fourth embodiment, it is assumed that theposition of a start point of allocated RBs and a length of the RBs areeach limited to a multiple of G (where G is a positive integer), theposition of each start point is limited to start from P, and the lengthis limited to start from K.

The fifth embodiment relates to a method for constructing RIVs, underthe condition that the start point ‘S’ of RBs starts from an offset Pand increases by T, and the length ‘L’ of RBs starts from another offsetK and increases by G. That is, the fifth embodiment describes a methodfor constructing RIVs under S∈{P, P+T, P+2T, P+3T, . . . }, L∈{K, K+G,K+2G, K+3G, . . . }.

FIG. 19 shows RIVs related to generable combinations of S and L valueswhen N_(RB)=30, T=4, G=2, P=1, and K=4 according to the fifthembodiment. The gray-colored part of FIG. 19 corresponds to combinationsof S and L values incapable of being actually generated when N_(RB)=30.RIVs are in the range of 0≦RIV≦48<2⁶, such that 6 bits are needed torepresent these RIVs.

If the range of available L values is limited by establishment ofL^(limit), the number of required bits may be reduced. Referring to FIG.19, if L^(limit) is set to 10 (L^(limit)=10), it can be recognized thata maximum RIV among RIVs is 25. In this case, because combinationshaving L values in the range of 12≦L≦28 may not be used, the range ofRIVs may be 0≦RIV≦21<2⁵, such that 5 bits are needed to represent theseRIVs as denoted by ‘N_(bit) _(_) _(required) _(_) _(lim)=5’bits.

The following equation 7 is made to calculate RIVs using combinations ofS and L values under the condition that N_(RB), T, G, P and K are given.In this case, the number of bits required for expressing the RIVs may becalculated in different ways according to L^(limit). Referring toEquation 7, L^(max) ^(_) ^(required) may represent the number ofactually available RBs. At this time, if there are remaining RBs due tothe granularity restriction, the number of the remaining RBs issubtracted from the number of actually available RBs, and thesubtraction result value may be represented by L^(max) ^(_) ^(allowed).In this case, in order to enable the actually-available RBs to be allallocated, L^(limit) is set to L^(Limit)=G·┌(L^(max) ^(_)^(required)−K)/G┐+K. In order to prevent the remaining RBs among theactually-available RBs from being allocated, L^(limit) is set toL^(Limit)=G·└(L^(max) ^(_) ^(allowed)−K)/G┘+K.

$\begin{matrix}{{{{{< {T\mspace{14mu}{and}\mspace{14mu} G\mspace{14mu}{are}\mspace{14mu}{Independent}\mspace{14mu}{starting}\mspace{14mu}{from}\mspace{14mu}{offset}\mspace{14mu}{values}\mspace{14mu} P\mspace{14mu}{and}\mspace{14mu} K}},{{respectively} > {{Step}\text{:}\mspace{14mu} T\mspace{14mu}{RBs}\mspace{14mu}{starting}\mspace{14mu}{from}\mspace{14mu} P}}}{Granularity}\text{:}\mspace{14mu} G\mspace{14mu}{RBs}\mspace{14mu}{starting}\mspace{14mu}{from}\mspace{14mu} K}\mspace{31mu}{{{if}\mspace{14mu}\left( {L - K} \right)\text{/}G} \leq \left\lfloor {{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}G} \right\rceil\text{/}2} + {{{mod}\left( {{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}G} \right\rceil - 1},{T\text{/}G}} \right)}\text{/}2}} \right\rfloor}\mspace{31mu}{then}\mspace{31mu}{{RIV} = {{{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}T} \right\rceil \cdot \left( {L - K} \right)}\text{/}G} + {\left( {S - P} \right)\text{/}T}}}\mspace{31mu}{else}\mspace{31mu}{{RIV} = {{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}T} \right\rceil \cdot \left\{ {\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}G} \right\rceil - {\left( {L - K} \right)\text{/}G} + \mspace{31mu}{{mod}\left\{ {{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}G} \right\rceil - 1},{T\text{/}G}} \right)}} \right\}} + \left( {\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}T} \right\rceil - 1 - {\left( {S - P} \right)\text{/}G}} \right)}}\mspace{31mu}{end}{{Required}\mspace{14mu}{bits}}\mspace{31mu}{N_{{bit}_{—}{required}} = \left\lceil {\log_{2}\left( {{RIV}_{\max} + 1} \right)} \right\rceil}\mspace{31mu}{{{if}\mspace{14mu}\left( {L^{{RIV}_{\max}} - K} \right)\text{/}G} \leq \left\lfloor {{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}G} \right\rceil\text{/}2} + {{{mod}\left( {{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}G} \right\rceil - 1},{T\text{/}G}} \right)}\text{/}2}} \right\rfloor}\mspace{31mu}{then}\mspace{59mu}{{RIV}_{\max} = {{{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}T} \right\rceil \cdot \left( {L^{{RIV}_{\max}} - K} \right)}\text{/}G} + \left\lfloor {\left( {N_{RB} - L^{{RIV}_{\max}} - P} \right)\text{/}T} \right\rfloor}}\mspace{31mu}{else}\mspace{59mu}{{RIV}_{\max} = {{{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}T} \right\rceil \cdot \left( {L^{{RIV}_{\max}} - L} \right)}\text{/}G} - 1}}\mspace{31mu}{{Where},\mspace{31mu}{{Without}\mspace{14mu}{limitation}}}\mspace{31mu}{{LIV}^{{RIV}_{\max}} = {{G \cdot {{round}\left( {{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}G} \right\rceil\text{/}2} + {{{mod}\left( {{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}G} \right\rceil - 1},{T\text{/}G}} \right)}\text{/}2}} \right)}} + K}}\mspace{31mu}{{With}\mspace{14mu}{limitation}\mspace{14mu} L^{Limit}}\mspace{31mu}{{L^{{RIV}_{\max}} = {\min\begin{Bmatrix}{{{G \cdot {{round}\left( {{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}G} \right\rceil\text{/}2} + {{mod}\left\{ {{\left\lceil {\left( {N_{RB} - P - K + 1} \right)\text{/}G} \right\rceil - 1},{T\text{/}G}} \right)\text{/}2}} \right)}} + K},} \\L^{Limit}\end{Bmatrix}}},\mspace{31mu}{L^{Limit} = {{G \cdot \left\lceil {\left( {L^{\max_{—}{required}} - K} \right)\text{/}G} \right\rceil} + {K\mspace{14mu}{or}}}},{L^{Limit} = {{G \cdot \left\lceil {\left( {L^{\max_{—}{allowed}} - K} \right)\text{/}G} \right\rceil} + K}}}}\;} & \left\lbrack {{Equation}\mspace{14mu} 7} \right\rbrack\end{matrix}$

In this case, because the above RBs are continuously allocated RBs,L^(Limit), L^(max) ^(_) ^(required), and L^(max) ^(_) ^(allowed) may berepresented as L_(CRBs) ^(Limit), L_(CRBs) ^(max) ^(_) ^(required), andL_(CRBs) ^(max) ^(_) ^(allowed), respectively.

Assuming that the number of actually available RBs is set to N_(VRB),some RBs having large indexes may not be allocated due to thegranularity restriction. In order to allocate such remaining RBs, N_(RB)may be set to N_(RB)=┌(N_(VRB)−K−P)/max(T,G)ℏ·max(T,G)+K+P. However,under this condition, if the remaining RBs are contained and allocated,the L value may include the number of imaginary RBs, i.e., N_(RB)^(imaginary)=S+L−N_(VRB). As a result, if the remaining RBs arecontained and allocated, the length of actually-allocated RBs is denotedby L−N_(RB) ^(imaginary)=N_(VRB)−S.

The exemplary embodiments described hereinabove are combinations ofelements and features of the present invention. The elements or featuresmay be considered selective unless otherwise mentioned. Each element orfeature may be practiced without being combined with other elements orfeatures. Further, the embodiments of the present invention may beconstructed by combining parts of the elements and/or features.Operation orders described in the embodiments of the present inventionmay be rearranged. Some constructions of any one embodiment may beincluded in another embodiment and may be replaced with correspondingconstructions of another embodiment. It is apparent that the presentinvention may be embodied by a combination of claims which do not havean explicit cited relation in the appended claims or may include newclaims by amendment after application.

The embodiments of the present invention may be achieved by variousmeans, for example, hardware, firmware, software, or a combinationthereof. In a hardware configuration, the embodiments of the presentinvention may be implemented by one or more application specificintegrated circuits (ASICs), digital signal processors (DSPs), digitalsignal processing devices (DSPDs), programmable logic devices (PLDs),field programmable gate arrays (FPGAs), processors, controllers,microcontrollers, microprocessors, etc.

In a firmware or software configuration, the embodiments of the presentinvention may be achieved by a module, a procedure, a function, etc.performing the above-described functions or operations. A software codemay be stored in a memory unit and driven by a processor. The memoryunit is located at the interior or exterior of the processor and maytransmit data to and receive data from the processor via various knownmeans.

The present invention is applicable to a transmitter and a receiver usedin a broadband wireless mobile communication system.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

What is claimed is:
 1. A method for receiving a downlink signal by anapparatus in a wireless mobile communication system, the methodcomprising: receiving common downlink control information including aresource indication value, RIV, wherein the RIV is mapped to a startindex S and a length L of consecutive virtual resource blocks, VRBs; andreceiving the downlink signal on the consecutive VRBs, wherein, ifY−1≦└X/2┘ is given, the RIV is mapped to the start index S and thelength L of the consecutive VRBs according to a relation ofRIV=X(Y−1)+Z, or else the RIV is mapped to the start index S and thelength L of the consecutive VRBs according to a relation ofRIV=X(X=Y+1)+X−1−Z), where X is denoted by X=└N_(VRB)/G┘, Y is denotedby Y=L/G, Z is denoted by Z=S/G, N_(VRB) a number of VRBs, and G is aninteger of 2 or more.
 2. The method according to claim 1, wherein, alength, N_(bit) _(_) _(required), of a bit field used for transmittingthe RIV is denoted by N_(bit) _(_) _(required)=┌log₂(RIV_(max)+1)┐,where RIV_(max) is denoted by RIV_(max)=└N_(VRB)/G┘·(└N_(VRB)/G┘+1)/2−1.3. The method according to claim 1, wherein the G value is 2 or 4 (G=2or 4).
 4. The method according to claim 1, wherein the consecutive VRBsare a set of distributed VRBs, DVRBs.
 5. A method for transmitting adownlink signal by an apparatus in a wireless mobile communicationsystem, the method comprising: transmitting common downlink controlinformation including a resource indication value, RIV, wherein the RIVis mapped to a start index S and a length L of consecutive virtualresource blocks, VRBs; and transmitting the downlink signal on theconsecutive VRBs, wherein, if Y−1≦└X/2┘ is given, the RIV is mapped tothe start index S and the length L of the consecutive VRBs according toa relation of RIV=X(Y=1)+Z, or else the RIV is mapped to the start indexS and the length L of the consecutive VRBs according to a relation ofRIV=X(X−Y+1)+(X−1−Z), where X is denoted by X=└N_(VRB)/G┘, Y is denotedby Y=L/G, Z is denoted by Z=S/G, N_(VRB) is a number of VRBs, and G isan integer of 2 or more.
 6. The method according to claim 5, wherein, alength, N_(bit) _(_) _(required), of a bit field used for transmittingthe RIV is denoted by N_(bit) _(_) _(required)=┌log₂(RIV_(max)+1)┐,where RIV_(max) is denoted by RIV_(max)=└N_(VRB)/G┘·(└N_(VRB)/G┘+1)/2−1.7. The method according to claim 5, wherein the G value is 2 or 4 (G=2or 4).
 8. The method according to claim 5, wherein the consecutive VRBsare a set of distributed VRBs, DVRBs.
 9. An apparatus for use in awireless mobile communication system, the apparatus comprising: areceiver; and a processor, wherein the processor is configured to:receive common downlink control information including a resourceindication value, RIV, wherein the RIV is mapped to a start index S anda length L of consecutive virtual resource blocks, VRBs, and receive adownlink signal on the consecutive VRBs, wherein, if Y−1≦└X/2┘ is given,the RIV is mapped to the start index S and the length L of theconsecutive VRBs according to a relation of RIV=X(Y−1)+Z, or else theRIV is mapped to the start index S and the length L of the consecutiveVRBs according to a relation of RIV=X(X−Y+1)+(X−1−Z), where X is denotedby X=└N_(VRB)/G┘, Y is denoted by Y=L/G, Z is denoted by Z=S/G, N_(VRB)is a number of VRBs, and G is an integer of 2 or more.
 10. The apparatusaccording to claim 9, wherein, a length, N_(bit) _(_) _(required), of abit field used for transmitting the RIV is denoted by N_(bit) _(_)_(required)=┌log₂(RIV_(max)+1)┐, where RIV_(max) is denoted byRIV_(max)=└N_(VRB)/G┘·(└N_(VRB)/G┘+1)/2−1.
 11. The apparatus accordingto claim 9, wherein the G value is 2 or 4 (G=2 or 4).
 12. The apparatusaccording to claim 9, wherein the consecutive VRBs are a set ofdistributed VRBs, DVRBs.
 13. An apparatus for use in a wireless mobilecommunication system, the apparatus comprising: a transmitter; and aprocessor, wherein the processor is configured to: transmit commondownlink control information including a resource indication value, RIV,wherein the RIV is mapped to a start index S and a length L ofconsecutive virtual resource blocks, VRBs, and transmit a downlinksignal on the consecutive VRBs, wherein, if Y−1≦└X/2┘ is given, the REVis mapped to the start index S and the length L of the consecutive VRBsaccording to a relation of RIV=X(Y−1)+Z. or else the RIV is mapped tothe start index S and the length L of the consecutive VRBs according toa relation of RIV=X(X−Y+1)+(X−1−Z), where X is denoted by X=└N_(VRB)/G┘,Y is denoted by Y=L/G, Z is denoted by Z=S/G, N_(VRB) is a number ofVRBs, and G is an integer of 2 or more.
 14. The apparatus according toclaim 13, wherein, a length, N_(bit) _(_) _(required), of a bit fieldused for transmitting RIV is denoted by N_(bit) _(_)_(required)=┌log₂(RIV_(max)+1)┐, where RIV_(max) is denoted byRIV_(max)=└N_(VRB)/G┘·(└N_(VRB)/G┘+1)/2−1.
 15. The apparatus accordingto claim 13, wherein the G value is 2 or 4 (G=2 or 4).
 16. The apparatusaccording to claim 13, wherein the consecutive VRBs are a set ofdistributed VRBs, DVRBs.